<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <div id="yeye" style="position: relative;">
        <div id="father" >
            <div id="son"></div>
        </div>
    </div>

<script>
    var son = document.getElementById("son");
    console.log(son.offsetParent);
    console.log(son.parentNode);
</script>
</body>
</html>